1. Technical Field
The present invention relates to a setting management system for managing communication parameters which are necessary for letting a device function as a communication device capable of data communication via a network according to a prescribed communication protocol.
2. Description of Related Art
In order to enable a network device (hereinafter simply referred to as a “device”) to execute data communication via a network, various parameters such as identification information on the device (IP address) and identification information on a gateway server (the so-called “default gateway”) and a DNS (Domain Name System) server (hereinafter collectively referred to as “communication parameters”) have to be set properly for the device. The setting of the communication parameters is generally implemented by various setting functions, including manual setting (setting by manual operation by a user) and automatic setting (setting according to a prescribed communication protocol such as DHCP (Dynamic Host Configuration Protocol) and NDP (Neighbor Discovery Protocol)).
The communication parameters which have been set by such setting functions can be changed arbitrarily to suit the status of use of the device. However, normal operation of the device can be negatively impacted in some cases if other parameters regarding a particular setting function are not changed properly together with the communication parameters.
For example, in cases where the setting of a communication parameter is realized by the automatic setting, a validity period (lease period) is generally assigned to the communication parameter set as above, and the communication parameter is updated to a new parameter at every lease period. If the communication parameter is changed by the manual setting function in the state with the automatic setting function enabled, the communication parameter will be updated automatically at the expiration of the validity period even if data communication is possible during the validity period, by which data communication which has been executed normally can become impossible after the expiration. Specifically, if identification information on the device that has been changed properly by the user is updated by the automatic setting function with timing unexpected by the user, data reception which has been possible up to that point can become impossible. Also data reception can become impossible if identification information on the gateway server or the DNS server that has been changed properly by the user is updated by the automatic setting function with unexpected timing.
A technique for avoiding the above problem has been proposed recently in Japanese Patent Provisional Publication No. 2001-34434 (paragraph No. 0043, for example). In the technique, when a manual operation is performed by the user to change a functional parameter (e.g. information indicating validity/invalidity of DHCP) regarding a particular setting function (into information indicating validity of DHCP, for example), the device checks whether the alteration involves a factor negatively impacting normal operation (e.g. disabling of an I/F operating under DHCP) and outputs a message (displays the message on its control panel) when there exists such a factor.
With the above technique, when a manual operation for changing a functional parameter regarding a particular setting function is performed by the user, an expected disablement of normal operation can be reported to the user. Further, the user is allowed to change other related parameters (e.g. a parameter indicating enabling/disabling of the I/F) together with the functional parameter, as described in Japanese Patent Provisional Publication No. 2001-34434.
However, in the above technique, the parameters that are referred to when checking for a factor negatively impacting the normal operation of the device are not communication parameters but parameters regarding the setting of hardware configuration (I/F, etc.) of the device even though the functional parameters are parameters regarding the setting functions (manual setting, automatic setting, etc.) for the setting the communication parameters. In other words, the above technique is not capable of informing the user that both a functional parameter and a communication parameter should be changed in conjunction with each other even if the functional parameter and the communication parameter are closely related to each other.
Considering that the communication parameters can be changed more frequently than the hardware configuration of a device, informing the user that a functional parameter and a communication parameter should be changed together as above can be regarded as a matter of more importance and necessity than informing the user that there exists a factor negatively impacting the normal operation based on the hardware configuration of the device. Therefore, a technique is desired that is capable of informing the user that a functional parameter and a communication parameter should be changed in conjunction with each other.